1. Field of the Invention
The subject invention relates to a filling apparatus for filling beverage containers with carbonated liquid, and more specifically to an improved filler valve arrangement for such an apparatus having a centrally located carbonated beverage tank.
2. Description of Related Art
Filling apparatus for filling beverage containers with carbonated beverage, e.g., beer and carbonated soft drinks, are large high-speed machines which can continuously fill 800 or more beverage containers per hour. Such filling apparatus have in the past been constructed according to either of two tank types: central tank and annular (or torroidal) tank. Generally, the filler valve components of central tank type machines are not interchangeable with those of annular tank type machines, and vice versa. Traditionally, the central tank type filling apparatus have been used for beer, whereas the annular tank type machines have been used for soft drinks. Although more recently, the industry has seen increasing acceptance of the annular tank type units for filling both soft drink and beer containers.
In a central tank type filling apparatus, an array of remote valve housings are fed with beer and CO.sub.2 via conduits from the pressurized central tank. The filler valves in the valve housings each comprise stacked disks or plates which are pressed tightly together and rotate between various positions to accommodate the vacuum/counter pressure/fill/snift operations. Examples of central tank type filling apparatus with the traditional disk valves are shown in U.S. Pat. No. 2,728,511 to Breeback, issued Dec. 27, 1955 and assigned to the assignee of the subject invention, and U.S. Pat. No. 5,295,520 to Acker, issued Mar. 22, 1994.
The inner valve bodies of the central tank-type disk valve have large surface areas which are pressed together in tight frictional contact to prevent leakage between the various openings. However, these compressed plates must rotate against each other. Rapid wear between the compressed plates of the disk valve is accentuated by the hard granular residue left by evaporated beer. Hence, a major disadvantage of the central tank type filling machines lay in its disk valves which characteristically exhibit poor pressure holding capabilities and require frequent maintenance due to rapid wear between the rotating inner valve body surfaces.
Annular tank filling machines, on the other hand, employ reciprocating filler valves which do not rely on large rotating surfaces to maintain pressure seals. Such reciprocating filler valves are located within the annular tank, having a lower section immersed in the liquid and a top section communicating directly with the pressurized CO.sub.2 for the counter-pressure and venting phases of the filling operation. Therefore, reciprocating filler valves receive liquid beverage and CO.sub.2 directly from, and vent directly back into, the annular tank. Reciprocating filler valves generally exhibit increased pressure holding capabilities and lower (more favorable) maintenance requirements. Examples of prior art reciprocating filler valves for annular tank-type machines may be found in U.S. Pat. No. 4,442,873 issued Apr. 17, 1984 and U.S. Pat. No. 5,150,740 issued Sep. 29, 1992, both in the name of Yun and both assigned to the assignee of the subject invention.
There are a great many central tank filling apparatus still in service. However, there is no know way to integrate the more reliable reciprocating filler valves, which require immersion in the liquid beverage, with the central tank type units which feed the remote filler valves via conduits.